1. Field of the Invention
The present invention concerns a device for heating vials containing samples and relevant solvents to be submitted to chromatographic analysis, as well as in case at least part of the sampling apparatus, in automatic samples for gas chromatography.
These automatic samplers comprise a series of test-tubes or vials, each containing a sample generally diluted in a relevant solvent, accommodated on a tray which drives them in succession to a drawing station. Here, a needle penetrates through the vial sealing septum and draws an amount of liquid (sample+possible solvent) of same, transferring it to the injector of a chromatograph.
2. Description of the Prior Art
Solvents used in gas chromatography are usually very volatile, with boiling points generally between 35.degree. and 70.degree. C. and considerable vapour tension even at room temperature. Furthermore, due to the sample characteristics of viscosity or solubility in the solvent used, it is often necessary to heat the vials and possibly the sample path inside the sampler almost as far as the chromatograph, at temperatures approaching the solvent boiling point. Heating must obviously be as much as possible controlled in temperature and homogeneous.
Solvents used are often flammable and/or toxic, it is therefore very important that solvent vapours escaping from the vial pierced septa do not stagnate in the ambient, but are removed and diluted with air or other gases so that they do not reach explosive and/or toxic concentrations.